Electric siren



Dec. 17, 1929. L. H. MILES ELECTRIC SIREN Filed March 29, 1,927 2 Sheets-Sheet 1 Fir-" L ELE- E I IN VEN TOR. LESTER H. M/L ES A TTORNE Y.

Dec. 17, 1929. L, H MILE 1,739,727

ELECTRIC SIREN Filed March 29. 1927 2 Sheets-Sheet 2 INVENTORQ LESTER H. 1 s

, ATTORNEY.

Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE LESTER.H. MILES, F IiOS ANGELES, CALIFORNIA mnormc SIREN Application filed March 29, 1927. Serial No. 179,210.

Another object of this, invention isto prov,

vide means whereby the siren rotor will drift freely after the electric motor has stopped.

A further object of theinvention is to provide an electricallydriven siren wherein the siren rotor operates on a bearing independent from the electric motor.

A still further object of the invention is to provide an electrically driven siren having novel means of connection between the siren rotor and the electric motor.

A further object of the invention is to provide a siren having curved vanes.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein: a

Fig. 1 is a side elevation of my improved siren. 1

Fig. 2 is a front view of the siren.

Fig. 3 is a central longitudinal section of my proved siren showing the operating parts thereof.

Fig. 4 is a section through the siren casing taken on line 44 of Fig. 1.

' Fig. 5 is a fragmentary section of the siren rotor taken on line 5-5 of Fig. 3, showing the clutchmechanism in an operative position.

Fig. 6 is a view similar toFig. 5 showing the clutch mechanism in an operative position.

Fig. 7 is a view similarv to Fig. 1 showing a modified form of siren rotor drive means in an inoperative position.

Fig. 8 1s a view similar to Fig. 7 showing clutch mechanism in an inoperative posltion.

Fig. 9 is a rear face view of a port1on of the siren rotor drive means.

Fig. 10 is a section taken on line 10 -10 of Fig.9,and.

Fig. 11 is a fragmentary sectlon showing the hub and a vane of the rotor.

Referring to the drawings by reference characters I have indicated a siren embodying the features of my invention generally at 10. As shown in the accompanying drawings the siren 10 comprises a casing indicated generally at 11. This casing includes a hollow cylindrical body portion 12 havin' a reduced cylindrical hub' 13 thereon. 'l he body 12 is also provided on its outer periphery with a plurality of spaced apertures or ports 14 as clearly shown 1n Figs. 1 and 4.

Thebody 12 is provided with a cover plate 15 which may be secured to the body by screws 16 or in any other suitable manner. This cover is preferably provided with a hollow cylindrical boss 17, the function of which will be more fullydescribed hereinafter.

Mounted within the-body 12 is a rotor 18. This rotor comprises a fiat circular plate 19 provided at its center with a hub 20 and on its outer periphery with a plurality of spaced flanges 21. From one end, ofeach alternate flange 21 a vane 22 extends and joins the hub 20 and from one end of each of the remaining flanges 21 I provide a vane 23 which terminates intermediate the flange and the hub 20. The vanes 22 preferably have a cutaway portion 24"(see Fig. 3) adjacent their 'throu hthe apertures at the ends of the space flanges 21 and through the ports 14 of the casing. As the air is forced outwardly and. the ports 14 are intermittently opened and closed by the rotor flanges 21 a loud'noise will be produced.

I The cut-away portions 24. of the vanes 22, theabsenceof a connection between the vanes 23 and the hub ,20 and the curvature of the vanes 22 and 23, all combine to lessen the resistance as the, rotor revolves while increasing the volume of sound produced.

The cut-away portions 24 of the vanes 22,

' and 'the'absence of a connectionbetween the vanes 23 and the hub also allow more air to enter the chambers between the vanes and thus a greater quantity of air may be forced out through the ports 14, thereby producing a much louder noise than if all the vanes ran direct to and were connected with the hub20.

juncture with the hub' 20. The vanes 22 and 1 The rotor 18 is shown as mounted on a we) I the rotor and provided with an enlargedv flange 27. The shaft and the rotor may be secured together as by screws 28 passing through the flange 27. The enlarged portion 26 of the shaft 25 is provided with a cylindrical recess 29 the function of which will be more fully described hereinafter.

The shaft 25 is adapted to be mounted in anti-friction bearings 30 which are shown as mounted in a boss or spider 31 in the horn 13 which is supported by a plurality ofe ually spaced ribs 32 integral with both the S8 31 and the horn 13. With this construction a sturdy, independent bearing is provided for the rotor 18. r

The rotor 18 is shown in the drawings as adapted. to be driven from an electric motor 33 which may be of any type desirable. The motor which has an armature shaft 34 is shown as secured to the cylindrical boss 17- of the cover plate 15 by countersunk screws 35. To the free end ofthe armature shaft 34 I secure a ratchet member 36 (see Fig. 5). having a plurality of flat surfaces 37. x

In the rear of the ratchet 36 I provide an enlarged washer 38, the peripheral diameter of which approximates the size of the aperture 29 in the enlarged portion 26 of the shaft 25. Between the washer 38 and the motor housing I provide a sleeve 39. The washer 38 serves to hold the rollers to be presently described,

the ratchet 36 I provide a plurality of rollers 40 correspondingin number to the number of surfaces 37 on the ratchet.

tion the rollers 40 willlie looselfy t When the siren is in an inoperative posibetween the ratchet 36 and the side walls 0 he recess 29 as shown in Fig. 5. When the ratchet 36 is revolved by the motor the rollers are forced outwardly b the flat inclined surfaces 37, and are we ged into contact with the side walls of the recess 29 as shown in Fig. 6, thus causing the shaft 25 to rotate and thereby rotating the siren rotor 18.

When the current to the motor 33 is cut off and the motor rotor slows down, the rollers 40 will cease to be wedged into contact with the surface of the recess 29, whereupon the rotor 18 may revolve freely. With this form of driving connection or clutch between the motor and the siren rotor the motor needs to be run only at intervals thereby effecting a great saving of electric energy while maintaming a constant sound signal.

In Figs. 7 and. 8 I have indicated a siren generally at 45 wherein a modified form of drive connection is provided between the motor and the siren'rotor. This siren 45 is similar to the siren 10 and comprises the casing 11 which includes-the hollow cylindrical body Fig. 10.

apparent that I have portion 12 and the cover plate 15. The hollow cylindrical boss 17 of this siren is longer than on the siren 10 to accommodate the modified form of driving connection.

Within the casing 12 I mount the siren rotor 18 which has been previously described in detail. The rotor 18 of siren 45 is mounted on a shaft 46 which is similar to the shaft 25 of siren 10 except for the configuration of the recess 47 in the enlarged portion 48. The enlarged portion 48 is provided with a flange 49 similar to the flange 27 of shaft 25, and countersunk screws 50 therein secure it to the siren rotor hub 20.

The aperture 47 of the enlarged portion 48 is provided with a plurality of grooves 51. The side walls of the grooves 51 are preferably tapered in the opposite direction to the direction of rotation as clearly shown in For rotatin the siren rotor 18 I secure to the motor'sha t 52 a collar 53 which through the medium of a coiled spring 54 and a tooth 55 drives another collar 56 which is loosely mounted on the motor shaft 52. The collar 56-is provided with a tooth 57 corresponding to the tooth 55 of collar 53.

.Secured to the collar 56 and having a head or stop 58 thereon I provide a screw threaded shaft 59. Upon this shaft I mount a member 60 having a plurality of lugs or teeth 61 and having a screw threaded aperture therethrough to match'the screw threads on the shaft 59.

When the electric motor is operated and the screw threaded shaft '59 revolved at high speed the member 60- will be caused by the screw threads to move towards the siren ro tor 18, whereupon the teeth 61 of member 60 will engage the grooves 50 in the enlarged portion 48 of shaft 46 'and'cause the shaft to rotate thereby rotating the siren rotor 18. When the electric motor is deenergized the teeth 61 of member 60 are forced, by the 0011- tinued rotation of the siren rotor, out of engagement witlithe grooves 51, thereby allowingthe siren rotor to freely drift and continue to produce a Ioudnoise even after the electric motor has stopped.

From the foregoing descri tion it will-be rovi ed a siren enibodying a plurality 0 novel features and which is simple in construction and eflicient 1n use.

What I claim is:

1. In a siren, a casing, a rotor in said casing, an electric motor associated with said 2. A siren including a casing, a rotor in said casing, said rotor including a plurality of vanes, a motor including a shaft associated with said casing, said rotor being supported in bearings independent of said motor and means to drive said rotor from said motor shaft, said drive means comprising clutch means whereby, when the motor armature operates, connect-ion is made between said rotor and said motor shaft causing said rotor to rotate at the same speed as the motor shaft and when the speed of said armature decreases the connection between said rotor and said motor shaft is broken, whereupon said rotor continues to rotate independently of said armature.

In testimony whereof, I hereunto afiix my signature.

LESTER H. MILES. 

